(1) SUMMARY OF THE INVENTION
The present invention relates to a sequenced gene encoding for a bacteriocin in Pediococcus acidilactici and in particular to a gene that is essential for the production of the functional bacteriocin, called hereafter helper protein, and to the cloned gene in a vector which is transformed into a bacterium. In particular, the present invention relates to a sequenced gene encoding for a bacteriocin derived from a plasmid in Pediococcus acidilactici.
(2) Prior Art
The pediococci are a diverse group of Gram-positive homofermentative lactic acid bacteria often found as saphrophytes on vegetable material (Gonzalez, C. F., and B. S. Kunka, Appl. Environ. Microbiol. 53:2534-2538 (1987); and Mundt, J. O., W. G. Beattie, and F. R. Wieland, J. Bacteriol. 98:938-942 (1969)). Commercially, pediococci are used in the fermentation of vegetables (Pederson, Bacteriol. Rev. 13:225-232 (1949) and meats (Smith, J. L., and S. A. Palumbo, J. Food Prot. 46:997-1006 (1983)).
Some strains of P. pentosaceus, P. cerevisiae and P. acidilactici have been found to contain resident plasmids although the roles of most of these remain unknown (Gonzalez, C. F., and B. S. Kunka, Appl. Environ. Microbiol. 46:81-89 (1983); Graham, D. C., and L. L. McKay, Appl. Environ. Microbiol. 50:532-534 (1985); and Raccach, M., CRC Crit. Rev. Microbiol. 14:291-309 (1987)). The association of raffinose fermentation and plasmid DNA has been reported (Gonzalez, C. F., and B. S. Kunka, Appl. Environ. Microbiol. 51:105-109 (1986)), as has been the ability of P. acidilactici to ferment sucrose (Gonzalez, C. F. and B. S. Kunka, Appl. Environ. Microbiol 53:2534-2538 (1987)). Moreover, there have been several reports which associate the production of bacteriocins with host plasmid DNA (Daeschel, M. A., and T. R. Klaenhammer, Appl. Environ. Microbiol. 51:1538-1541 (1985); Gonzalez, C. F., and B. S. Kunka, Appl. Environ. Microbiol. 53:2534-2538 (1987); Graham, D. C., and L. McKay, Appl. Environ. Microbiol. 50:532-534 (1985); and Bhunia et al, J. Applied Bact. 65:261-268 (1988)). It was shown by Gonzalez, C. F. and B. S. Kunka (Appl. Environ. Microbiol. 53:2534-2538 (1987)) that bacteriocin production was encoded by a 9.0 kbp plasmid pSRQ11 in P. acidilactici PAC1.0. Further work (Pucci, M. P., E. R. Vedamuthu, B. S. Kunka and P. A. Vandenbergh, Appl. Environ. Microbiol. 54:2349-2353 (1988)) demonstrated that the bacteriocin of P. acidilactici PAC1.0 was active against a wide spectrum of gram positive lactic acid bacteria, and also against Listeria monocytogenes. This anti-listerial activity was observed in broth and on agar plates, as well as in some dairy products. Inhibition of L. monocytogenes by this bacteriocin, PA-1, has also been noted in fermented semi-dry sausage (Berry, E. D., M. B. Liewen, R. W. Mandigo and R. W. Huthine, J. Food Protection 53, 194-197 (1990)) and fresh meat (Nielsen, J. W., J. S. Dickson and J. D. Crouse, Appl. Environ. Microbiol. 56, 2142-2145 (1990)). The cloning of genes for the production of the bacteriocin has not been described and this would be useful for producing bacteriocin in significant quantities in genera unrelated to Pediococcus, or enhancing production in the pediococci.
Cloned Gram-positive genes for different unrelated proteins have been shown to express in Escherichia coli (Gilmore, M. S., Curr. Top. Microbiol. Immunol. 118:219-234 (1985); Rogeson, J. P., R. G. Barletta, and R. Curtiss III, J. Bacteriol. 153:211-221 (1983); and Smorawinska, M., J. C. Hsu, J. B. Hansen, E. K. Jagusztyn-Krynicka, Y. H. Abiko, and R. Curtiss III, J. Bacteriol. 153:1095-1097 (1983)).